The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Automotive vehicles typically utilize an internal combustion engine to provide the power to operate the vehicle. Internal combustion engines generate heat due to the combustion process and it is necessary to continuously remove the excess heat from the vehicle's engine in order to maintain the operating temperature of the vehicle's engine at a specified level.
The usual method of removing this excess heat is an automotive cooling system. The cooling system utilizes a coolant pump which pumps coolant through the vehicle's engine to absorb the excess heat and then this heated fluid is pumped to a heat exchanger or radiator which removes the excess heat by performing a heat exchange process with ambient air. The coolant which has been cooled by the radiator is returned to the engine and the process continuously repeats itself. Typically, the temperature of the coolant is maintained at a minimum level using a thermostat or some other type of control system.
In order to reduce the size and thus the costs of the radiator, the automotive designer strives to have the radiator operate in the most efficient manner. One method used to maximize the efficiency of the radiator is to control the flow of ambient air through the radiator. This is accomplished by providing a fan which draws the ambient air through the radiator and then providing a fan shroud which ensures that the maximum amount of air is drawn through the radiator. The maximization of ambient air flow requires that the fan be located within the fan shroud.
A common problem with fans is the noise they generate during operation. The noise components generating the sound radiated by the cooling fan are tonal and overall noise. Tonal noise is a result of the rotation of the fan blades. Both tonal and overall noise are equally important for most cooling fans. Obstacles upstream and downstream of the fan create airflow disturbance and induce pressure fluctuation. Fan noise is typically caused by wall pressure fluctuation in the fan and shroud. This noise issue can be addressed by configuring the fan shroud to release this pressure thereby reducing the noise radiating from the cooling fan. The shroud must keep the same or equivalent airflow performance of the old design.